Pull towers for pulling upon a chain connected to damaged portions of a vehicle have long been known in the automotive frame and body straightening industry and are represented by such prior patents as my U.S. Pat. No. 3,338,083, directed to a particular ram structure used to pull upon the chain. Such pull towers may be floor mounted, as shown in my '083 patent or may be mounted on and part of a vehicle work rack structure, such as shown in my U.S. Pat. No. 4,313,335. In that patent, a pull tower is mounted on a carriage which slides around the periphery of a vehicle work rack. In either case, floor mounted or rack mounted, the pull tower must be effective and easy to use and be able to be sturdily positioned on a supporting surf ace. Additionally, because the damaged portion of the vehicle may be at different heights and different situations, the height of a pulley attached the pull tower for changing the direction of travel of the chain must be easily adjustable. Particularly with tight profit margins, the less set-up time for making the pull, the better for the shop. At the same time the connection of the chain direction changing pulley to the tower must be sufficiently sturdy so that it does not inadvertently slip or become loose when the chain is placed under the significant tensions used in making a pull on a vehicle.